FAQs - Apex Seals

What are the clearance requirements for your 2 mm apex seals? The seals are a drop in replacement for Mazda stock seals. Rotor to seal clearance is .002 - .004 (2 - 4 thousandths). The length is pre-set so do NOT adjust the length of the seals. They are of a different alloy from Mazda seals, with different characteristics as they get hot, so do not adjust the seals. Drop them in and go :)Do RA seals cause excessive wear on the rotor housings? Our seals are harder than OEM seals. This property is what prevents the seals from fracturing under high heat/high horsepower conditions. A side effect of the increased hardness of our seals is that, under some circumstances, the wear rate on the housings is slightly higher than with OEM seals. However, the lack of catastrophic engine damage when the seals are overstressed, more than out weighs the costs of any possible housing wear. After all, broken OEM seals are certain to destroy one or more expensive engine parts - housings, rotors, etc. We've seen reports on some rotary forums about various apex seals causing "galling" or "chatter marks" on the rotor housings. What do you know about this problem?? Whether they want to talk about it or not, ALL third party seals (Atkins, Hurley, RA Classic Seals) CAN result in chatter marks or "galling" on the rotor housings under some specific conditions. We have taken apart several engines, using RA seals, and have NOT seen this problem. We're torn down engines with RA seals that were bent from detonation, and NOT seen this problem. On the other hand, we have personally seen one engine, using our seals, with this problem, AND engines with Hurley and Atkins seals with this problem. No 3rd party apex seal manufacturer is immune. This is a conditional problem, and since we are not there with the thousands of engines that are using our seals, it is impossible to determine exactly what causes this issue. It MAY be caused by high oils temps combined with a low amount of oil in the combustion chamber. In fact, the amount of oil Mazda injects into the combustion chamber is really not sufficient for long engine life with ANY seal. Since we don't seem to see this problem on aviation engines (we generally mix two stroke oil with the fuel and run more oil than Mazda suggests) it may indicate the high temps and low lubricating oil for the seals may be the cause. Again, this is a common problem and is NOT SPECIFIC TO RA seals. As a builder, do I need to check my clearances if I use your seals? Emphatically YES YES YES. Any builder will ALWAYS check all clearances, regardless of what seals he/she is using. Our seals go through multiple quality control checks both by sub contractors and five additional quality control checks during final packaging. None the less, always check your clearances BEFORE reassembling and running your engine. If you do see any problem with the clearances on the seals, contact us before your reassemble. It will be much easier for us to work with you in the event of a question if you always follow this procedure.What alloy is used in the apex seals? When we decided to produce our own apex seal, the goal was to develop a product superior to those currently available. It quickly became apparent that the job was far more complicated than simply selecting a promising alloy from a catalog, and hoping for the best. A metallurgist and materials specialist were contracted to study other apex seals and identify their composition, strengths and weaknesses. We then chose an alloy and heat treatment that would meet our goals. Even with professional help, testing was still required to confirm that the chosen material would yield the specified properties. Needless to say, the research taken to select an alloy was time consuming and not cheap. Therefore, in the interests of protecting our investment, the identity of the alloy used in our seals will remain proprietary. What we can tell you is that the seals are not made out of a derivative of gray cast iron, which is used in other seals, including Mazdas.Do I get any guarantee with the seals ? Yes - we guarantee them against defects in manufacturing and material for 60 days from date of purchase. We guarantee they will be a direct replacement part for stock Mazda seals. Defective seals will be replaced.Are these dual spring apex seals? Yes, in fact, the springs are exactly the same design as the stock 86-95 parts and are interchangeable. We were not very impressed with the longevity of Mazdas three-piece apex seal, but the dual spring configuration was a good thing. We feel that the dual spring suspension offers the best support and control of the apex seal at all rpms. Our Classic Springs are suitable for all street cars (including Turbo cars). We do suggest using RA Racing Springs/Mazda Springs for HIGH BOOST and nitrous applications, Do you offer a 3mm version of your seal? YES. Please be aware, that the 3mm seals are offered as seal sets only configured for single springs. Since the 3mm seal sales is expected to be a relatively low volume part, they will not be offered with springs as a package. The seal is configured to accept factory springs. Why aren't you offering dual spring 3 mm seals? Dual spring seals do offer a little bit more stability at very high RMS (9000+) BUT they cause more wear on the rotors. 3mm dual springs seals are also used by cars that run with super high boost. (By the way, our 2mm seals are in use successfully in cars with boost up to 35 psi). Bottom line is that the number of cars that actually need the 3 mm dual spring set up is very small so we are not offering that set up. If you DO want a 3 mm dual spring configuration, you can machine the 3mm seals for the dual spring configuration. Remember, the material we use is VERY HARD and cannot be machined using high speed steel. What engines will your 3 mm seals fit? The 3 mm seals will fit 1974 - 1985 13B engines. They will also fit 1986-1995 13B engines that have been modified for 3 mm seals. Do you recommend your Classic apex seals for high performance use? The seals were designed to surpass, by a wide margin, the toughness and wear resistance of all other metal seals on the market. Our seals are currently running in hundreds of cars all over the world, including numerous high boost drag racers (35 psi+ of boost). These cars are racking up miles faster than we can report, but the best news is that nobody has reported any problems. In fact, we were actually happy to hear about a turbo II that experienced severe detonation, under boost, due to problems with the secondary injectors. The engine survived with no apparent damage to the seals The short answer is yes, we do recommend them for modified engines, but as with all internal engine parts installed in non-stock, performance applications, use them at your own risk. This is a standard practice within the performance and racing parts industry. The reason is simply that once an engine is modified to a competition level, the engine becomes experimental. It is not unheard of to have highly modified engines pop even before they have left the shop. Will these seals work on 12A engines? Do you plan to make any for 12A engines?No and yes. The 2 mm seals will not fit 12A engines BUT we now DO SELL 12A seals. The 12A seals do NOT come with springs. You will need to purchase the Mazda stock 12A springs.